Alright yeah, perhaps I misinterpreted those particularly strong friendships as moirallegiances. I thought it was primarily about feelings-jams. But a moirallegiance is more than that, as Hussie explained on the forums:
"The purpose is to pacify a partner who is dangerous. It's not all about being platonic soul bros forever."
Which is potentially accomplished by feelings-jams in piles, but doesn't mean that all close relationships built around sharing feelings are moirailships.
Maybe I fell victim to:
It's often ambiguous especially among young trolls whether a bond formed between an acquaintance is true moirallegence, or the usual variety of platonic involvement.
http://www.mspaintadventures.com/?s=6&p=004301
Honestly I think Karkat and Sollux at least had a moirailship. They were best bros who often calmed each other down. Sollux was bipolar, and Karkat was always blustering, and then they would suddenly chill out while talking. They did everything except literally pap.
Karkat had an unspecified "pact" with Eridan, a pact which Eridan apparently wasn't aware of. What was the meaning of that? I always assumed Eridan was just a good guy (because it certainly wasn't FEFERI stopping him from killing the land dwellers, worst moirallegence ever). But actually, I feel like there are strong hints that it was his close friendship with Karkat which kept him pacified. Which would be moirallegence.
Kanaya <> Karkat... They don't interact all that often, but she *also* has a pacifying effect on him. Though more like a mother, heh (Dolorosa). He describes her as his "other best friend". So it's certainly *hinted* at.
Gamzee he just cusses at and insults, and Gamzee never calms him down. Until Gamzee goes insane and then their moirallegence operates perfectly, briefly, then ends offscreen.
As for the past few updates, I'd argue that Dave & Karkat is intentionally vague but pale. They're best bros foremost, and in conversations Dave explicitly calms Karkat down with bizarre effectiveness. While Karkat tries to be the filter that Dave lacks.
So yeah. Maybe trolls are supposed to commit to just one moirallegiance. I think Karkat is just the village two-horned device for calming and being calmed. And there's nothing wrong with that